Remote control system



C. A. BROOKS REMOTE oo NTRoL SYSTEM Sept. 22, 1931.

Filed Aug. 23, 1928 Patented Sept. 22, 193l OIE* PENNSYLVANIA UNITED s'rmissA CHARLES A. dBROOKS, yO13" SWISSVALE, PENNSYLVANIA, ASSIGNOR TO THE UNION 'SWITCH & SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A CORPORATION PATENT OFFICE! REMOTE CONTROL SYSTEM Application led August 23 1928. Serial No. 301,626.

' My invention relates to remote control y)systems of the type involving a control station, a plurality of remote sta-tions, and a normally closed circuit extending from the control station to the remote stations and including in series a code transmitting contact in the control Astation and code selecting means at each remote station.

One object -of my invention is thespro vision, in a system of the character `de scribed, of means at a, remota station for placing a low resistance shunt v across the control circuit in the event of abreakin the circuit, so that such circuit may still be operated between the control station and such.

f energizedby means lhaving nothing to do remote station. 1

I will describe one form of control system embodying my invention, and will then point out the novel features thereof in claims.

The accompanying drawing is a diagrammatic view showing one form of control system embodying my invention'. lReferring to the drawing, the reference character G designates-acontrol station, and 25 the reference characters A0 A1 and A2 desig nate three remote stations. Locatedin the control station is a code transmitting relay Cl provided with a normally closed code transmitting contact 3. Each remote station is provided with a code receiving relayvR and with selecting means S governed by a normally open back contact 21 ofV the associat'ed code receiving relay R. Each remote `station is also provided with a code trans'- back contact 3. The control station is further provided with -a code receiving relay R the back contact 21 of which'controls a code receiving selector means SGf The contact 3 of each code transmittingrelay C", C1 and C2 @is normally\excludedfrom the control cir- .cuit,but may be included in the control circuit when a return indication relay.T, T1 or T2 is energized.

The normally closed control circuit is from battery 2 at the control station G, through contact 3 of code transmitting relay C, wire 4, relay R", battery 2, contact 30--31 of return indication relay T0, wires 32 and 33,-

y special4 relay D at station A, wire 34 relay mitting relay C having a normally closedv R1, battery 2A, contact 5-6 of return indica- 'the code transmitting relay C at control station G, and that it includes each of the code receiving relays R0, R1 and R2, but that itrdoes not include the code transmitting contacts 3 of relaysCO, C1 and C2 at theremote stations A,'A1 and A2.

When a signal, is to be transmitted Jfrom the control station, relay yC is intermittently with my present invention, with the result that contact 3 is intermittently opened. This causes intermittent de-energization of the' receiving relays R0, R1 and R2, with the result that the selectors S0, S1 and S2 are operated in the usual and well known manner'to select one of the remote stations and to give a suitable indication at the selected station.

When a signal is to be transmitted from remote station A1 to the control station G, the return indication relay T1 is first energized, thereby opening the main circuit at contact 5 6 of this relay and closing-a shunt across the main circuit, which shunt passes from battery 2A through contact 5-14 of relay T1, back contact 3 of code transmitting relay C1 and wire 16 to line wire 13. Relay C1 is then intermittently energized to intermittently open its back contact 3, with the result that the receiving relay R at the control station G is intermittently de-energized to operate the selectors SG. When-the return indication is completed, relay T1 again becomes deenergized, so that the parts are restored to their normal positions wherein they are ready for the transmission of a signal from/the control station Gag l and the signal is then -transmitted by contact 3 of relay C".

A system of the type thus far described is disclosed and claimed in anapplication fdr Letters Patent of the United States filed by C. S. Snavely on May 14, 1929, Serial No. 362,948, for remote controlling apparatus.

I will now assume that a break occursin the control circuit between stations A1 and A2, as for example at point 22 in wire 9. It will\be seen that in the absence of any special provision this would prevent the transmission of 'a signal from the control station G to either remote station A0 or A1. Located at station A1, however, is a special relay D which is included in the normal control circuit and/which. is therLefore cle-energized each time that the code transmitting contact 3 of relay C is opened. Relay D .controls a slow pick-up device E, the circuit* being from terminal B of a suitable source -of current, through contact 17 of relay D,

operating winding of device E, and a' back contact 18 of a cut-out, relay F to terminal O of the same source of current. The time interval required for contact 19 of the slow pick-up device E to close is substantially greater than the maximum interval lduring which contact 3 of relay C is open while a code is being transmitted from the control station G. It follows that contact 19 of the device E remains open during the transmission of the code from station G. If Lthe control circuit becomes open, however, at a point such as at 22, relayl D will remaindeenergized', and contact 19 of theslow pickup device E will close. The cut-out relay F willthen become energized through a pick'- up circuit which includes contact 19 of the device E. Cut-out relay AF is provided with a stick circuit which passes from terminal energized, it will remain energized as long i l:ses

B, through back contact 17 of the special relay D, front contact 2O of relay F, and the winding of relay F to terminal O. It follows that when the relay F once becomes as relay D- remains de-energized. When relay F becomes energized, its back contact 18.

opens, thereby de-energizing the slow pickup deviceE. The closing of contact 23 of the cut-out relay F closes a shunt across the control circuit at station A1, which shunt passes from wire 7, ythrough wire 24, front contact 23 of relay F, and wires 25 and 16 to line wire 13. The break in the line atV 22 will also cause relay D at station A to remain open long enoughto energize relay F at this station, thereby 'closing a second tact-23, wires 25,116, 13, 37 and 36, Contact 35,\wires 38 and 33, relay D, wire 34, land i' 35 of relay F. With this latter shuntclosed,V

the operation of the code transmitting contact 3 at station G will cause operation of the code receiving relays R0 and 'R1 at stations A and A1, and so it follows that the operator atstation G can transmit signals to stations Ao and A1. When the break in the` line is repaired, relay D will at station` A1 become energized, with the result that Vthe stick circuit for relay F will be opened, so that this relay will become de-energizedand will `remove the shunt across the line at station A1. The circuit for relay D, by which this relay becomes energized when the break in the line vis repaired, is from battery 2B, through contact .10-11 of relay T2, wires 12, 13, 16 and 25, contact 230i relay F, wires 24 and 8, relay D, Wire 9, and relay R2, to battery 2B.

While station A1 is transmitting, relay D Will be deprived of current, so thatthis relay will be open and relay F will be closed. As

soon as station A1 stops transmitting, relay 'D will close and relay F will open.

the slow' pick-up device E, and the cut-out y relayF, so that when a break in the line occurs between any two remote stations, communication can still be maintained between the control station and allof 'the remote stations up to the point at which the break has occurred.

Although I have herein'y shown and de- 'i scribed only one form of remote control system embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1 In a remote control system, a normally closed circuit extending from a control station to a plurality of remote stations, said circuit including ,in series a code transmitting device at the control station, code transmitting means at each remote station and a' source of energy at each station, a protection relay at each remote station except the last serially included in said circuit, means at each remote station-except the last for placing a shunt across said circuit at such station so that the local source of current and the local coderesponsive means are included in the portion of the circuit leading to the control station and the local protection relay is included in the portion of the circuit leading to thepnext more remote station, means `whereby each of said protection relays causes the corresponding shunting means to complete the correspondin shunt when said normally closed circuit is roken for a time interval greater than the maximum time interval said circuit is broken duringthe transmission of codes by the code transmitting means, whereby upon a break in the circuit at any point the protection relay at each remote station becomes de-energized to cause the operation ofthe associated shunting means and remains de-energized until the circuit therefor is completed by the shunt applied by the relay at the more remote station or by the repair of the break in said circuit.

2. In a remote control system, a normally closed circuit extending from a control station to at least'a first and second remote station, said circuit including in series a code transmitting device at the control station, code responsive means at each remote station and a source of energy at each station, a protection relay at the first remote station serially included in said circuit, means at said first remote station for placing a shunt across the circuit at such station so that the local source of current and the local code responsive means are included in the portion of the circuit leading to the control station and the protection relay is included in the portion of the circuit leading to the second remote station, means whereby said protection relay causes the shunting means to complete the shunt when said normally closed circuit is broken for a time interval greater than the lmaximum time interval said circuit is broken during the transmission of codes by the code transmitting means, whereby upon a break in the circuit -between said first and second remote stations, the protection relay becomes deenergized to causev the operation of said shunting means and remains (le-energized until the circuit therefor is completed b the repair of the break in said normally c osed circuit.

In testimony whereof I aix my signature.

CHARLES A. BROOKS. 

